Sensor

Stereo and tri-stereo capture

When the satellite captures the same area from two or three angles in a single pass — required for DSM and DTM generation.

Fig. 1 Stereo capture acquires the same scene from two viewing angles in a single pass. The convergence angle between the two rays encodes 3D depth — photogrammetric software triangulates every visible point. Tri-stereo adds a third angle to handle urban occlusions.

Stereo capture means the satellite tilts to acquire the same scene from two different viewing angles in a single pass — usually one looking forward and one looking back. The angular difference (called the convergence angle) lets photogrammetric software triangulate the 3D position of every visible feature. Tri-stereo adds a third viewing angle, improving accuracy especially in urban areas where buildings occlude one of the views.

What it enables

Stereo or tri-stereo captures are required to generate DSMs (digital surface models) and DTMs (digital terrain models). They are also useful for cleaning up shadow occlusions in dense urban environments. Without stereo, you cannot produce true 3D measurements from satellite imagery.

What it enables

Read more on the Geopera blog